1. Field of the Invention
The present invention relates to force feedback haptic devices (a.k.a., hand controllers), particularly to six-degree-of-freedom hand controllers with interchangeable instruments involving revolute or prismatic jointed handles.
2. Background Art
Force-reflecting master hand controllers have been used to drive robotic systems, and to provide an interface to a computer system that allows the user to input spatial position and to feel forces in response to his or her movement.
In U.S. Pat. No. 6,593,907, issued on Jul. 15, 2003 to Demers et al., a tendon-driven hand controller that provides powered translation in three degrees of freedom, and powered rotation in three degrees of freedom is described.
The six-degree-of-freedom (6-DOF) hand controller is especially useful in surgical simulation. A virtual force may be presented as if it were acting at any location on a handle held by the operator. The force that is felt can therefore mimic the feeling of surgical instruments as they are used in an operation.
To this point, it has been possible to simulate instruments with single handles, such as a scalpel, but many instruments involve their own degree-of-freedom mechanisms, such as two members connected by a revolute joint. Scissors, forceps, clamps and rongeurs fall under this category. Moreover, the varieties of such instruments number in the tens of thousands, as they are created for cutting and manipulating tissue in many different surgical procedures.
In spite of the large variety of instruments, a limited number of handles for hand controllers have been designed for these instruments, since the human hand has a limited number of shapes and sizes.
There do exist surgical simulators with fixed handles and a limited number of degrees of freedom. Rosenberg, in U.S. Pat. No. 5,731,804, issued on Mar. 24, 1998, describes a 4-DOF hand controller with a gripper handle. This device is intended to simulate an endoscopic surgical instrument, in which the working surfaces are at the end of long shafts inserted through holes in the patient's body. The simulated endoscopic surgical instrument however appears to be permanently part of the hand controller.
Likewise, U.S. Pat. No. 6,684,129, issued to Salisbury, Jr. et al. on Jan. 27, 2004, discloses the operation of the master controller of the robotic surgical system from Intuitive Surgical Inc. The master controller has six degrees of freedom, plus one degree for activation of a gripper. The handle, however, is fixed to the device, and designed to enable the operator to manipulate the various tools of the surgical system.